Comprehension
The process of copying genetic information from template strand of DNA into RNA is called transcription. It is mediated by RNA polymerase. Transcription takes place in the nucleus of eukaryotic cells. In transcription, only a segment of DNA and only one of the strands is copied into RNA.
Question: 1
Why is only the DNA strand with $3^\prime \rightarrow 5^\prime$ polarity transcribed into RNA, while the complementary strand with $5^\prime \rightarrow 3^\prime$ polarity is not transcribed?
Why is only the DNA strand with $3^\prime \rightarrow 5^\prime$ polarity transcribed into RNA, while the complementary strand with $5^\prime \rightarrow 3^\prime$ polarity is not transcribed?
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All nucleic acid polymerases (DNA polymerase and RNA polymerase) synthesize new strands exclusively in the $5^\prime \rightarrow 3^\prime$ direction. Consequently, they must read their template strands in the $3^\prime \rightarrow 5^\prime$ direction.
Updated On: Aug 16, 2026
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Question: 2
Why must newly transcribed eukaryotic hnRNA undergo the process of splicing before it can become functional mRNA?
Why must newly transcribed eukaryotic hnRNA undergo the process of splicing before it can become functional mRNA?
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- Exons are Expressed sequences (coding).
- Introns are Intervening sequences (non-coding) that must be removed via splicing.
Updated On: Aug 16, 2026
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Question: 3
Name the two additional processing modifications that hnRNA must undergo, besides splicing, to transform into fully functional, mature mRNA.
Name the two additional processing modifications that hnRNA must undergo, besides splicing, to transform into fully functional, mature mRNA.
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Post-transcriptional modifications of eukaryotic hnRNA include:
1. Capping: Methyl guanosine triphosphate added at the $5^\prime$-end.
2. Splicing: Introns removed, exons joined together.
3. Tailing: Poly-A tail added at the $3^\prime$-end.
Updated On: Aug 16, 2026
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Question: 4
Explain why only one of the two complementary DNA strands is transcribed into RNA during the transcription process. Provide two distinct reasons.
Explain why only one of the two complementary DNA strands is transcribed into RNA during the transcription process. Provide two distinct reasons.
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Transcribing only one template strand ensures that each gene produces a single, predictable mRNA transcript, keeping the flow of genetic information clear and efficient.
Updated On: Aug 16, 2026
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Top Questions on RNA Transcription
- Which of the following are the post-transcriptional events in an eukaryotic cell? (A) Transport of pre-mRNA to cytoplasm prior to splicing.
(B) Removal of introns and joining of exons.
(C) Addition of methyl group at 5' end of hnRNA.
(D) Addition of adenine residues at 3' end of hnRNA.
(E) Base pairing of two complementary RNAs.
Choose the correct answer from the options given below:- NEET (UG) - 2025
- Biology
- RNA Transcription
Study the items of Column-I and those of Column-II:
Choose the option that correctly matches the items of Column-I with those of Column-II:
- CBSE Class XII - 2025
- Biology
- RNA Transcription
- Which of the following statements are correct with reference to a transcription unit in DNA? A. A transcription unit in DNA is defined primarily by three regions: promoter, structural gene and terminator.
B. The promoter is said to be located towards the $5'$-end of the structural gene.
C. The promoter is a DNA sequence that provides binding site for RNA polymerase.
D. The promoter defines the template and coding strands.
E. The terminator is located towards the $3'$-end of the coding strand and it defines the end of the process of transcription.- NEET (UG) - 2026
- Biology
- RNA Transcription
- Four different transcription units are shown below. Choose the option with the correct image.
- CBSE Class XII - 2026
- Biology
- RNA Transcription
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